
@media screen and (min-width: 650px) {
  body{
    margin: 0;
  }
  .title{
    border: 1px solid #d9d9d9;
    width: 600px;
    margin: 0 auto;
    margin-top: 100px;
    border-bottom: none;
    padding: 12px 24px;
    border-radius: 4px 4px 0 0;
  }
  ul{
    width: 648px;
    margin: 0 auto;
    border: 1px solid #d9d9d9;
    border-top: none;
    list-style-type: none;
    padding-left: 0;
    border-radius: 0 0 4px 4px;
  }
  a, a:active{
    padding: 12px 24px;
    display: block;
    border-top: 1px solid #f0f0f0;
    color: #1890ff;
    text-decoration: none;
    transition: background-color .3s;
  }
  a:hover{
    background-color: #fafafa;
  }
}
@media screen and (max-width: 649px) {
  body{
    margin: 0;
    background-color: #f5f5f9;
  }
  .title{
    color: #888;
    padding: 15px;
    font-size: 12px;
  }
  ul{
    margin: 0;
    padding: 0 15px;
    list-style-type: none;
    background-color: #fff;
  }
  li{
    border-top: 1px solid rgba(0,0,0,0.1);
    font-size: 16px;
  }
  li:nth-child(1){
    border-top: none;
  }
  a, a:active{
    padding: 10px 0;
    text-decoration: none;
    display: block;
    color: #000;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  .arrow{
    display: block;
    width: 15px;
    height: 15px;
    margin-left: 8px;
    background-image: url(data:image/svg+xml;charset=utf-8;base64,PHN2ZyB3aWR0aD0nMTYnIGhlaWdodD0nMjYnIHZpZXdCb3g9JzAgMCAxNiAyNicgeG1sbnM9J2h0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnJz48cGF0aCBkPSdNMiAwTDAgMmwxMS41IDExTDAgMjRsMiAyIDE0LTEzeicgZmlsbD0nI0M3QzdDQycgZmlsbC1ydWxlPSdldmVub2RkJy8+PC9zdmc+);
    background-size: contain;
    background-repeat: no-repeat;
    background-position: 50% 50%;
  }
}